It is a very important distinction. It is the difference between three sizable but incremental advances - rehabilitating unsuitable donor organs, the potential to use pig organs, and elimination of immune rejection - and the far, far greater advance of being able to grow entire patient-matched organs from scratch as needed with no donor.

Being shackled to the need for a donor organ for tissue much thicker than a centimeter is a big drag on the progression of this field. It is a function of blood vessels, largely - being able to create scaffolds of sufficient complexity and size with the right chemical guides to allow formation of blood vessel networks is still not there yet. Hence the need for the natural scaffold of the donor organ.